Transmission mechanism



Dec. 7 1926.

E. S. CLARK TRANSMISSION MECHANISM Filed Nov. lOl 1925 2 Sheets-Shee?l l INVENTOR Eug ,9. lar/1,

,0 ATTORNEYS Dec. 7 1926.

E. S. CLARK TRANSMISSI ON MECHANI SM Filed Nov. 10, 1925 2 Sheets-.Sheet 2 INVENTOR Y y BY ATTORNEYS WITNESSES Patented Bec. 7, 1926.

UNITED STATES v ELLEF S. CLARK, OF ROYAL OAK, IMCHIGAN.

TRANSMISSION MECHANISM.

Application filed November `1D., 1925. Serial No. 68,183.

The present invention relates to a change speedtiansmission mechanism capable of a wide range of utility,- but in its preferred :forni primarily adapted for transmitting power from the crank shaft of an automobile engine to the propeller shaft of the car.

An object of the vinvention is to provide a planetary transmiion which in its preferred embodiment is capable of being operated by a standard gear shift lever, and which like standard sliding gear transmissions, whica are now so operated, will give three. speeds ahead and one speed in reversel rldhe advantages of planetary gear transmission over the commonly used sliding gear transmission are well recognized. Planetary transn'iission avoids clashing of gears, inasmuch as gears are always in mesh, is much more suitable for operation by an unskilled driver, and has the great advantage that wnen the car is in high speed or direct drive, the gear set revolves asa "unit with the fly `wheel without any gea-rs turning on each other, thus insuring a quiet drive with a minimum of friction.

The only type of planetary gear transmission mechanism which has been commercially used with any success, is the present type of Ford transmission, which is capable of giving only two speeds ahead and one speed in reverse. lt has been heretofore considered impracticable to vprovide a planetary transmission gii'f'ing three speeds ahead and one in reverse without rendering the mechanism unduly fcon'iplicated.. The two speed ahead type is only suitable for small light cars, and it is an object of the present invention to provide a three speed ahead type which will be of simple, 'practical construction, and which is primarily intended for supersedingk the usual sliding gear transmissions used on large and heavy cars.

lVith the above noted and other objects in view, the invention consists in certain novel features of construction and combinations and arrangements of parts, as will be more fully hereinafter set forth and pointed out iii-the claims. The invent-ion may be more fully understood from the following description in connection Awiththe accompanying drawings, wherein Fig. 1 is a view in longitudinal sectionk through a transmission mechanism embody-- ing the invention. f

Fig. 2 is a transverse sectional view on the line 2-2 of Fig. 1.

`radially disposedspindles 24:.

' Figs. 8, 4 and 5 are longitudinal sectional viewsv through modified types of transmis-- sions.

l shall first refer to the mechanism show" in Figs. l and 2, inasmuch as this mechanism not onlyI illustrates the novel principles involved, but shows a preferred forni of transmission Yfor ordinary automobile purposes. In these figures I have used the reference character 10 to designate the rear end of crank shaft or motor shaft. Keyed upon said shaft is the driving element 11 of a conventional type of disc clutch, said clutch including` a driven element 12, operating lovers 13 for engaging the driving` and driven elements, a clutch collar 11i for actuatlng the levers, and a control'lever 15 for the clutch collar.A

rlie control lever may be pedal operated or otherwise suitably manipulated bythe driver of the car. The collar 14 is slidably mounted upon the usual propeller shaft 16 -in a conventional manner, and a spring 17 encircling the propeller shaft or driving shaft 1G normally tends to urge the collar 19iforwardly and engage the clutch. The motor shaft 10 has the hub 18 of a driving gear 19 keyed thereto, the gear 19 being preferably bevelled. The hub 2O of the driven element 12 of the clutch, is keyed to a hollow driven shaft 2lturning freely on the motor shaft 10. The hollow shaft 21 is preferably lined with suitable` bearing material 22. It will be understood that any suitable type of roller bearings might be employed instead of the hardened bushings `or bearing sleeves illustrated in Fig. 1.

Near its forward end, the driven shaft 2l carries means for supporting and retaining one or more sets of planetary gears. I have shown a simplel form of gear retaining mechanism, or planetary gear carrier including enlarged head 23 on theshaft 21 fromr which project a suitable number o-f Preferably a balanced spindle arrangement is used, two spindles at diametrically opposite points of the head 23 ordinarily serving the purpose.

A greater number of spindles may be employed if desired, but in most instances the additional balance and interlocking gainedy will not justify the added complication of the construction. Upon each spindle there is mounted a set of planetary gears or pinions 25, 26, 27. These gears are fixed togetherfor simultaneous free turning on the ll l) spindles 24e, and may if desired, be'integral with each other as shown.

Turning freely on a bearing sleeve 28 which encircles the driven shaft 21, is a hollow shaft 29, provided at its forward end with a bevel gear 30. Bevel gear 30 and the bevel driving gear 1) are always mesh with the innermost gears 27 of the spindle sets. lt is necessary to provide ine means for optionally holding the gear 30 against rotation. YVith this end in View l may conveniently l'ey the hub of a brale drinn 31 to the hollow shaft 29, this drum encircled by a brel-:e band 32 operated -y convenient manner (not shown) to -ii the drum and loci; the shaft 29 and its issociated gear 30 against.rotation;l A bearsleeve encircling the hollow shaft 29 s surrounded by another hollow shaft carryinel a bevel Oear meshing with the planetary gears 26. Shaft 34 preferably forms the hub a bralce drum 36 similar to drum 31, and encircled by an associated brake band 37.

Turning freely on the motor shaft is a relatively large reverse gear 3S, the hub 4ot' this gear turning on tl'ie shaft 10 at a point between the driving gear 19 and the motor. The. gear 38 is bevelled for engagement with the outer pinions of the planetary set, and may have a brale drum 239 bolted thereto as at 40, and encircled by brake band a1.

lt will be noted that the spindles which carry the planetary gear sets are inclined rearwardly or in a direction away from the motor. This inclination will depend entirely upon the speed ratios which it is desir d to establish between the motor shaft and propeller shaft, and upon the relative sizes of the drivi g gear 19 and sun gear 30. lf the speeo'ri itio at the intermediatespeed is to be two to one, the spindles 2d would be disposed at right angles to the motor sha-ft, and the gears 19 and 30 would be of equal size as willv be readily understood. For speed ratios of less than two toene, the spindles will incline in the direction shown in Fig, 1; while for speed ratios greater than two to one, they would incline in the. opposite direction or toward the motor. iin adf'antage of the spindle inclination is that fewer gearsvmay be used than' otherwise possible to obtain the desired speed ratio,

cfa s rlhe inclined spindles necessitate the use of bevel gears for ooaction with the planetary pinions7 thereby obtaining a more positive intermesh, a better balancing, and a more compact structure; lt may be noted that the bevel gears at each side of the spindles are dislied and in effect nested torender the tructure compact.

Before describing the modifiedA types of transmission shown in Figs. 3 toV 5, it may eifnently the construction is simplified.V

ism in slowspeed, brake band 37 is applied to the drum 'l6,.loclring the. gear 35 against rotation. The clutch is stillout. The inhing engagement of the planetary 00 with the gear 35 will cause planetary movement of the gear sets and their :rindles and consequent rotation of the drivshal't 21 to overcomeits load and drive i i the clutch member 12 to the pros raft 15. rl`he pin connection which rave illustrated at 4t2 between the member 12 and the propeller shaft is of course, merely diagrammatic and subject to oonsiderable change.

To obtain an intermediate speed, the drum 36 is released and thebrake band applied to the drain 31, locking gear against movement. 'l1 his causes a similar action to taire place. lla-netary gear sets travel aroundthe sun gear 30, which being smaller than the gear Vwill result in, a higher speed being imparted torthe driven shaft 2l. it both the slow speed andthe. second or intermediate speed, all vof the-gearswhich are not directly connected with the gear 19, are turning idly under the inflnence'of the planetary gears with which they are in mesh.

At high speed'I drive-directly through the clutch 11', 12., all of the brakebands being released and' tlleclutch beingthrown in to directly couple the motor shaft 10 andpropellerv shaft ist'. high speed, which is the speed commonly.l used, both the planetary gears and the sun 'ge'ars'rotate as a unit with the motoi` shaft. This gear assembly assures an'additional flywheel effect' on the motor, and the entire assembly turns without any ofthe gears turningone uponfthe other. At high speed therefore, the drive is substantially'frictionless as compared to the sliding gear transmission m which some interine'shing gears areturning'oneaclrotherf fdd il tl lil() lill lill) maximum of power isv obtained onthe reverse. VIt will be evident however that even if low speed and reverse speed were similar, gear 38 would still be larger than gear 353, since drivegear andreverse gear rotate in the same direction Vin which the planetary gears revolve; while thev opposite is-true relative to the low speed gear. Therefore, they would give entirely different speed ratios between low speed and reverse gears even if these gears were of equal size (assuming all of the planetary gears to be of equal size).

In Fig. 3 I have shown a preferred arrangement of gearing for obtaining two speeds forward and one 'speed in reverse. It will be noted that the construction is generally vsimilar to the construction of Fig. l. In this figure however, I have shown the Vdevice on a smaller and more diagrammatic scale, and have'omitted the shaft linings and bearing sleeves for the salie of clarity. In Fig. 3, l0a indicates the motor shaft, and 19atlie driving gear carried thereby. The hollow driven'shaft 2lLL carries the radially projecting spindles f 24al mounting planetary' gear sets which include only two gears 25 and 27a. High speed is obtained by a direct drive through the clutch mechanism of Fig. l, and low speed is obtained by locking a sun gear 35a against rotation. This sun gear has a bearingon the driven shaft 9.1, and carries the usual brake drum 35L encircled by operating band 37a. The reverse gear 38a meshes with the `gears 25 of the planetary sets and carries ya brake. drum 39a and associated band lll. i The gears 27a of the planetary set mesh with the drive gear 192L and low speed sun gear 35a.

For two speed engines, it is desirable that the slow speed ratio be greater than two to one, and with this end in view it.

will be noted that the spindles 24 incline forwardly instead of rearwardly, and that the slow speed driven gear 35Z1 is larger than the driving gear 19a. This arrangement greatly increases the slow speed ratio shown in Fig. l. The operation of the device will be evident from the previously discussed operation of the three speed type of gear set. Holding either brake drum 36a, 39l against movement will Ycause the planetary system to rotate about the sun 'gear locked by the drum.

l have not shown any of the details of 'the control mechanism by which the driver regulates the application of the brake bands to scie` tively change speeds. It may be noted however, that with the type of transmission shown in Fig. 3, the brake bands may be controlled by foot pedals as in the ordinary Ford construction. In the types of transmissions using three or more speeds ahead, the control is preferably effected through a conventional type of gear shift I levei, such as is employed in cars using av Vstandard shift. It will be obvious however,

that the method and means for applying the vbrakes forms no part of the present inven- In Fig. 4 Ihave shown a gear set or transmission mechanism for giving three speeds ahead and one in reverse, but in this Ainstance the spindles 24h and their associated gear sets 25h are carried by and rotate with the motor shaft 10b instead of carried by the driven shaft. The spindles and their gears thus act as driving, instead of power transmitting elements. The driven shaft 2lb 'carries a driven gear 13b. I provide the low speed gear 30h, the intermediate speed gear 351 and the reverse gear 38h. The gears 30, 35", 38b carry associated brake drums 50 for co-operation with brake bands 5l, and loching any of the gears against rotation will impart movement to the driven gear 19" to transmit power to the propeller shaft in accordance with fthe ratio of the locked gear and the driven gear.

The showing of Fig. 5 is in all respects similar tothe transmission mechanism of Fig.` l, except that I have added an additional reverse gear 60, and an additional speed gear (ill The reverse gear 6() gives a l-v reverse speed lower than the reverse gear 38C, while the additional gear 6l gives lower speed thanr the low speed obtained through gear 35, Inasniuch the mechanism of Fig. 5 operates on the same principle as that shown in Fig. l, no detailed description thereof is believed necessary. This mechanism is peculiarly adapted for heavy w `rl; where more f than three speeds ahead are desirable.

It will of course be evident that the gear designs might be so modilied as to give a super speed ratio, that is to say, a higher speed ratio than is obtainable on a direct drive. For all ordinary purposes such a speed ratio would not be desirable inasmuch as I desire to eliminate friction as far as possible at the high speed.

It will be noted that I may obtain any number of reverse speeds up to two, and any number of ahead speeds up to four, without unduly complicating the construction of the apparatus, since the radial spindle arrangement makes it practicable to compound the gears without materially complicating the construction. The arrangement of the radial spindles which carry the planetary gear sets is such, that the mechanism is always evenly balanced.

i-is indicative of the simplicity of the invention, reference may be had to the two speed set of Fig. 3, in which it will be noted that only seven gears are employed.

The arrangement which requires the spindles to be inclined either forwardly or rearwardly rather than at right angles to the ti i) isol motor; shaft, minimizes the.- number 'of gears necessary to effect proper operation, simplifies the construction, consequently reducing the cost of manufacture, and adding to the efficiency, of the transmission.

Various changesand alterations might be made in the general form and arrangement of parts described, without departing from th'e invention. Hence I' do not wish tolimit myself to thedetails set forth, but shall considermyself at'liberty lto make such changes and alterations as fairly fall wit-hin the spirit and scope of theappended claims. Among'these I particularly wish to mention the means forl controllingthe sun gears, 30, 35, 38, etc.` iVhile for the sake of clarity. of description onlyplain drums andassociated brake hands haveheen mentioned hereinl and shown in the drawings, it is to he understood that I do not limit' the mechanism to this particular form of brake, but that anysuitable form of friction brake may he used, such as the single disc, multiple disc, conetype, internal expanding type, plain brake shoe type, or any other wellrlrnown form.

1. The combination with a driving shaft and a drivinogear rigidly secured thereto, of a loaded hollow driven shaft turning freely on the drive shaft, a plurality of spindles fixed to and projecting radially from the driven shaft, sets of rigidly connected planetary gears turning freely on the spindles, one gear of each set meshing with the driving gear, a` plurality of'k differentl sized sun gears mounted to turn freely about the axis of the driving shaft, said sun gears meshing with thegearsof the planetary-setszand norA` mally idling as the planetary setszare rotated bythe driving gear,- vand means for selectively holding' any; sun@ gear againstt movementv to` effect. planetary movement of:V the planeta-ry'setsand their spindles, andi conf sequent` rotation ofithe driven shaft by which the.` spindles .arecar-ried, a: clutch mechanism for. directlyy coupling the.I drive shaft and driven shaft,l whereby the driving gear, planetary gears, andfsun gears Willbe locked against turning movement relattive to each other, andwillrotate as a unit \v=it'l1,the drive shaft'.v

Tlhe combination with laf drive shaft: and a driving gear rigidly secured theretmyofa leaded hollow' driven shaft turning freely on thevdrive shaft, ai plurality of spindles carried by, and projecting radiallyfromthe driven shaft, axesof said;spindlesbeing inelinedy relative to the axis of their -.sup port: ing shaft, sets .of rigidlyconneetedplanetary gears turning freely on the spindles, `one-gear of each setzmeshingwtlrthe -drivingfgean a plurality of: sun gears of" various sizes mountedto turn freelyahoutvthe axis of the drivingshaftf, and disposed on opposite sides of the spindles, saidsun gearsmeshing with the vgears of lthe planetary se.ts,imeans forse.n lectively holding any 'sunfgear againstymovement to effeetf planetary movementiof the planetary sets anda'their spindles, and; rota,- tion tof the' driven shaft in. a. direction dependingupon the side of; the spindles on which the lockedsungear is` disposed, a

clutch mechanism forcdirectly coupling the drive shaft and.;y driven shaft, wherebyl` the drivinggearplanetaryn gears andx sun gears will; leel locked against a turningmovementrelative to each other, and will rotate; as a unit with` the drive shaft,

ELLEF 'Si' CLARK. 

